这篇文章主要介绍如何实现鼠标拖动改变DIV等网页元素的大小，文中介绍的非常详细，具有一定的参考价值，感兴趣的小伙伴们一定要看完！
1.初次实现
1.1 html代码
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>div change width by drag</title>
<script src="../jQuery/jquery-1.8.3.min.js" type="text/javascript"></script>
</head>
<body>
<h2>div change width by drag</h2>
<div id="pos" ></div>
<div id="myDiv" ></div>
</body>
</html>1.2 js代码
var eleLeft = $('#myDiv').offset().left;
var isMouseDown = false;
var borderLen = 4; //左右边框
$('#myDiv').bind({
mousedown:function(e){
var ele = $(this);
var rightPos = eleLeft + ele.width() + borderLen;
if(rightPos-5 <= e.pageX && e.pageX <= rightPos){
isMouseDown = true;
}
},
mousemove:function(e){
var ele = $(this);
var rightPos = eleLeft + ele.width() + borderLen;
$('#pos').text("x:"+e.pageX + " eleLeft:"+eleLeft+" rightPos:"+rightPos);
if(rightPos-5 <= e.pageX && e.pageX <= rightPos){
ele.css('cursor','e-resize');
}else{
if(!isMouseDown){
ele.css('cursor','auto');
}
}
if(isMouseDown){
ele.width((e.pageX-eleLeft-borderLen)+'px'); //新鼠标位置-div距左-borderLen
}
},
mouseup:function(e){
isMouseDown = false;
}
});1.3 结果
只能往左拖动使div宽度变小，往右拖动没有用！原因往右拖动鼠标mousemove事件无法被div捕获了。拖动时也很难停下来！所以得改进。
2.再次改进
$('#myDiv').bind({
mousedown:function(e){
var ele = $(this);
var rightPos = eleLeft + ele.width() + borderLen;
if(rightPos-5 <= e.pageX && e.pageX <= rightPos){
isMouseDown = true;
}
}
});
$('body').bind({
mousemove:function(e){
var ele = $('#myDiv');
var rightPos = eleLeft + ele.width() + borderLen;
$('#pos').text("x:"+e.pageX + " eleLeft:"+eleLeft+" rightPos:"+rightPos);
if(rightPos-5 <= e.pageX && e.pageX <= rightPos){
ele.css('cursor','e-resize');
}else{
if(!isMouseDown){
ele.css('cursor','auto');
}
}
if(isMouseDown){
ele.width((e.pageX-eleLeft-borderLen)+'px');
}
},
mouseup:function(e){
isMouseDown = false;
}
});这次解决了上述问题，可以往右拖，并且随时可以停下来了。到这里就完成了吗？NO!
当我引入一个其他div，并且阻止mouseup事件冒泡情况怎么样呢？答案是，拖动到这个其它div上放开鼠标后无法停止下来！
<div id="otherDiv" ></div>
$('#otherDiv').mouseup(function(e){
//e.preventDefault(); //阻止默认行为
e.stopPropagation(); //阻止事件冒泡(导致body捕获不到mouseup事件)
});3.完美解决
拖动停止可能受到其它元素的干扰，怎么解决？想到一些弹出层点击其它其它地方隐藏的功能，让我想到了，加一个遮罩层，让mouseup事件总是可以响应，不就搞定了嘛！
$('#myDiv').bind({
mousedown:function(e){
var ele = $(this);
var rightPos = eleLeft + ele.width() + borderLen;
if(rightPos-5 <= e.pageX && e.pageX <= rightPos){
isMouseDown = true;
//创建遮罩层，防止mouseup事件被其它元素阻止冒泡，导致mouseup事件无法被body捕获，导致拖动不能停止
var bodyWidth = $('body').width();
var bodyHeight = $('body').height();
$('body').append('<div id="mask" ></div>');
}
}
});
$('body').bind({
mousemove:function(e){
var ele = $('#myDiv');
var rightPos = eleLeft + ele.width() + borderLen;
$('#pos').text("x:"+e.pageX + " eleLeft:"+eleLeft+" rightPos:"+rightPos);
if(rightPos-5 <= e.pageX && e.pageX <= rightPos){
ele.css('cursor','e-resize');
}else{
if(!isMouseDown){
ele.css('cursor','auto');
}
}
if(isMouseDown){
ele.width((e.pageX-eleLeft-borderLen)+'px');
}
},
mouseup:function(e){
isMouseDown = false;
$('#mask').remove();
}
});
$('#otherDiv').mouseup(function(e){
//e.preventDefault(); //阻止默认行为
e.stopPropagation(); //阻止事件冒泡(导致body捕获不到mouseup事件)
});4.完整代码和最终效果
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>div change width by drag</title>
<script src="../jQuery/jquery-1.8.3.min.js" type="text/javascript"></script>
</head>
<body>
<h2>div change width by drag</h2>
<div id="pos" ></div>
<div id="myDiv" ></div>
<div id="otherDiv" ></div>
</body>
<script type="text/javascript">
$(document).ready(function(){
var eleLeft = $('#myDiv').offset().left;
var isMouseDown = false;
var borderLen = 4; //左右边框
$('#myDiv').bind({
mousedown:function(e){
var ele = $(this);
var rightPos = eleLeft + ele.width() + borderLen;
if(rightPos-5 <= e.pageX && e.pageX <= rightPos){
isMouseDown = true;
//创建遮罩层，防止mouseup事件被其它元素阻止冒泡，导致mouseup事件无法被body捕获，导致拖动不能停止
var bodyWidth = $('body').width();
var bodyHeight = $('body').height();
$('body').append('<div id="mask" ></div>');
}
}
});
$('body').bind({
mousemove:function(e){
var ele = $('#myDiv');
var rightPos = eleLeft + ele.width() + borderLen;
$('#pos').text("x:"+e.pageX + " eleLeft:"+eleLeft+" rightPos:"+rightPos);
if(rightPos-5 <= e.pageX && e.pageX <= rightPos){
ele.css('cursor','e-resize');
}else{
if(!isMouseDown){
ele.css('cursor','auto');
}
}
if(isMouseDown){
ele.width((e.pageX-eleLeft-borderLen)+'px');
}
},
mouseup:function(e){
isMouseDown = false;
$('#mask').remove();
}
});
$('#otherDiv').mouseup(function(e){
//e.preventDefault(); //阻止默认行为
e.stopPropagation(); //阻止事件冒泡(导致body捕获不到mouseup事件)
});
});
</script>
</html>
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